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Startram — Maglev Train To Low Earth Orbit
Zothecula writes "Getting into space is one of the harder tasks to be taken on by humanity. The present cost of inserting a kilogram of cargo by rocket into Low Earth Orbit (LEO) is about US$10,000. A manned launch to LEO costs about $100,000 per kilogram of passenger. But who says we have to reach orbit by means of rocket propulsion alone? Instead, imagine sitting back in a comfortable magnetic levitation train and taking a train ride into orbit."
Now, how is this going to work?
Faster! Faster! Faster would be better!
Every step towards "Galaxy Express 999" is a step in the right direction.
If I'm going to fantasize about shit that will never be built, I'd rather dream of the sexbot. Oh perfect robotic woman---who is always horny, cooks and cleans, never wants diamonds, has no parents, never drones about about some bitch at work, never cheats, never complains about wanting a bigger house or nicer car---how I dream of thee.
SJW: Someone who has run out of real oppression, and has to fake it.
I'm assuming the weather control satellites will steer hurricanes away from this monstrous sitting duck?
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
So will the spaceport will be built at Sodor?
"That's the way to do it" - Punch
Looks that the investment, time, resources, etc should be orders above of the ones needed for a space elevator, and even that one is pretty hard to ever happen.
I can't see anything impractical or horrifically energy-intensive about this system.
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1. Requires no materials we don't already have
2. Would allow for continuous launches. This tube could be used every 15 minutes or so for another payload
3. Fairly massively spaceships could be launched this way
4. Once you get into LEO, getting around in space is relatively easy and cheap.
Downsides : the forces involved here are extreme. There's enormous magnetic fields, the whole structure is suspended in the air, it's over 1000 miles long, and depends on various complex pieces of tech to not rip itself apart. If the vacuum leaks or the plasma window fails or a magnet gets too much current, a chunk or even the whole damn launcher could spectacularly fail.
In addition, the estimated costs have got to be a factor of 10 too optimistic. 60 billion dollars? For something constructed of tens of thousands of miles of superconducting cable and a structure made to aerospace engineering tolerances that is 1000 miles long? Even 600 billion sounds optimistic for something that large.
So, triple it for a realistic estimate: $180 billion. Now, that sounds like a lot of money, but when you consider that the total amount of money flushed down the toilet for the Iraq war will probably be an order of magnitude above that, it's play money. We just have to convince people that there's oil in LEO.
a rail gun you can ride?
Supplies!
The energy requirements to get into orbit are practically the same no matter what method you use. Yes there is some savings from air resistance if you do it at a slower speed but it's not that much.
The only savings will be from a safety standpoint or similar. The energy costs will still be enormous.
This is nothing new...
Linear magnetic launchers have long since been considered...I read papers about then in the 80's...and there were a number of tests and prototypes that were looked at for this, and a number of sci-fi books have written about the device.
The engineering did not appear to be impossible just a large expensive project that no one wanted to fund, and there were concerns about it being used as a weapon as you just don't quite put the projectile/"train" in orbit and make sure it drops on the desired target with a high suborbital velocity.
I have never seen it called a mag-lev train...but it is more or less a standard magnetic linear accelerator and has been considered many times before.
Image 4 looks way too much like an 1850's Toile pattern for this to possibly be a serious attempt to devise a way to get to space.
I like the idea of building it on the ground then mag lev'ing it up. Makes building it a lot easier....
20 years is in my lifetime and 60 billion is less than 4 years of NASA's current budget. So 20 years of NASA's budget should easily be able to pay for this AND still have money for other stuff.
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" there is a superconducting cable on the ground carrying 200 million amperes, and a superconducting cable in the launch tube carrying 20 million amperes, at an altitude of 20 km there will be a levitating force of about 4 tons per meter of cable length"
That works out to an energy density of (mgh)=1.5e9 J/m. Multiply that by 1600 km, and you get 2.5e15 J, or half a megaton, equivalent to the yield of a small hydrogen bomb. Anyone ever see a superconducting magnet quench?
Falling space junk, meteorites, and terrorist. Which one takes out the $60B elevator first?
Uses already available technology?
What like teleportation? If we're using already existing technology- why not teleport stuff up into space.
OK- OK- so we have no Star Trek like teleportation yet... we also don't have space-trains yet either.
Don't get me wrong sounds neat- if you ignore that it's an easy terrorist target/war target; vulnerable to natural disasters (cannot be moved); we have no concept of what it would realistically cost to build something like this- and you have the whole concept of NIMBY- where my back yard is a 500 mile radius- because if one of these things comes and shoots out at high velocity and isn't shooting straight (yeah, I know she said that) - no prediction on where this will go.
I don't want to be a downer- think it sounds fine- I just hope the negatives have been explored. Interesting idea really.
"That's the way to do it" - Punch
The thing that makes this such a ridiculous engineering project is the requirement to carry humans, who can't be subjected to more than about 3 g's. The length of the track is inversely proportional to the acceleration, so if you're sending up steel I-beams that can withstand 3000 g's, you can shorten the track to 1 mile rather than 1000 miles. Tanks of water and rocket fuel can also be subjected to a lot more than 3 g's.
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I was reading through it and initially thought it was just flinging the train from the ground up... but apparently it needs a TWELVE MILE HIGH RAMP!... that is not practical. If you used Mount Everest to get a head start it would help but it wouldn't get it near enough to that mark to matter. How the hell does anyone think building this would be possible?
the space elevator ideas are less crazy and they're kookoo for cocopuffs...
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Even before that. The Man Who Sold the Moon.
Ignorance killed the cat. Curiosity was framed.
It only has to be 1000 miles long and 12 miles tall!
Can we go back to making more cost effective wind turbines, please?
Did I accidentally browse to "Popular Science Online"?
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In the US at least, we can't even get funding for maglev trains ON THE GROUND. Until the economy is better (in, oh in another 500 years or so) nobody is going to fund something like this.
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A little shorter than that. At the acceleration they're talking about you're in space in 5 minutes. You'd probably need a shower/bath after shitting yourself on the ride up considering you hit some atmosphere head on after exiting a tube going 25,000 mph.
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For high g cargo it makes total sense, nothing too crazy required.
They assume 3g as a max. I bet you could do 6 pretty easy. Reading up, looks like if you are reclined it could be 10+ even for untrained folks.
I'll beat you there in my flying car.
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Mt. Everest !!
29,002 ft = 5 miles
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...but better suited for a sci-fi novel rather than any serious contemplation. Look at all the trouble we have with building tall buildings AND magnetic installations. We are no where NEAR ready to take on something like this.
Kind of like the space elevator. Another concept that's several hundred years away from practicality, if ever.
I'd rather see us spend some real effort in improving the tech we currently have and are stuck with for the foreseeable future.
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Whereas if you have a SPSS with a collimated high-power MASER beam with a range of 300 miles, you also can carve "CHA" onto the surface of the moon.
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
Make the acceleration track a helix and see if you can keep the gs down to 3gs with a reasonable diameter on the helix. I don't know, but I am not going to take a ride on it in my lifetime.
Which direction do you think fuel costs are going to go over the next 20 years?
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British Rail doesn't exist any more. On topic, if a simple rail line from London to Birmingham (with a stop at Chipping Norton so Rupe can call in on Dave) will cost $50G before overruns, I suspect that $60G has a decimal point in the wrong place.
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On the other hand if you CAN do 3g you might as well. Sure, MOST people could handle 5 or 10, but practically EVEYBODY can do 3. And if you're trying to convince all the 80 year old rich dudes to invest in this thing, you better be sure they can ride on it without breaking a rib or having their heart give out.
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A really REALLY big trebuchet. That should do the trick.
Didn't Wile E. Coyote commission the construction of one of these to help propel himself so that he could catch the Road Runner? We could try asking him how that worked out before we commit to building our own.
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I remember when I first learned how electromagnets work and built some of my own, some the experiments I conducted included the "levitation" by use of the magnetic field, one thing I ran into time and time again was, when the distance increased to a certain distance the levitating magnet would suddenly flip over and come crashing down on the bottom magnet with both gravity and magnetic attraction to accelerate it.... hmmm.... train on top of levitating magnet..... uh, no thanks!
The technology to send electricity long distances with low losses was invented by Tesla, it's not exactly new. You don't need 0 resistance, you just need it to be low enough to still be economical.
It's an old idea - run the rails up a mountainside, and launch the craft from the end. It save a first stage.
But the biggest challenges are mudane. I did not notice any safety configuration for when the current fails and the power is no longer available to support the magnetic separation. The unpowered mode of this structure is unstable.
I suppose you could lower it each time you finished a launch, but then you have to spend the power to raise the whole thing again. I would expect they would build it on the ground and the cables would have automatic takeup/retraction (that's a lot of cable!), so it could be lowered.
Is it just my observation, or are there way too many stupid people in the world?
No, that's the same problem with just running the tube on the ground - when you exit, the pressure forces at orbital velocity will tear any vehicle apart. Build one tough enough to hold together and it will burn up from friction. Plus the losses at seal level will mean you would need far, far more speed than orbital velocity to "coast" to space.
That, of course, presumes you're willing to deal with the 16,000psi pressures, continuous immersion in salt water, and the enormous buoyant force that would come with an underwater tube.
Is it just my observation, or are there way too many stupid people in the world?
Centripetal forces.
Is it just my observation, or are there way too many stupid people in the world?
If my math is close, if you double the g you cut the length required in half.
Still, a 500 mile long tube 20 miles in the air seems a bit silly.
10-20 miles long seems more reasonable, but the g forces get a little nutty.
Think about the stresses that this structure will be under! Nevermind the power requirements for a MAGLEV. Maybe the people who dreamed this tried to beat alcoholism by taking LSD ? ->reference to other insane slashdot news posting.
Cripes in the 50s a cartoon character could get a cheap ACME rocket and get into orbit! Well, try that is. Is the fact that ACME is no longer in business the barrier? I mean what we need is more ACME products damnit! It's not that hard people!
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This 1000-mile long passenger-safe rail gun which has to be vacuum-sealed with one-way vents will be cheaper than conventional rockets in the long run?
No, silly, it's a 1000-mile long passenger-safe coil gun which has to be vacuum-sealed with one-way vents will be cheaper than conventional rockets in the long run!
Do you consider 3200 kilometers a reasonable diameter for the helix?
"They redundantly repeated themselves over and over again incessantly without end ad infinitum" -- ibid.
seal level
I think you just won malapropism of the week there.
That's the level seals are found on, nominally 0m altitude, right?
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
Does that tube stay in the air all the time?
If it does, then doesn't that take the output of a power plant (or more?) all it's own...plus add a plant (or 2) for maintenance/redundancy. That doesn't sound that cheap to operate unless it is sending a LOT of stuff to LEO. Their estimate seems to be the (additional) energy to launch something, not lifting the tube itself (and presumably keeping there)
If it doesn't, i am having a hard time imagining it going up/down gracefully EVERY time...Who gets to test it and how?
Have to wonder where this could be built that wouldn't mind the permanent no-fly zone 100 miles long or so. Plus no earthquakes, hurricanes, etc. No vandals trying to sell your cable for scrap (ok, disconnecting the cable and getting slingshot to orbit from the tension is a good mental image) ;p ;)
How are lightning strikes going to affect operation? It seems inevitable. Perhaps you just get an extra g or 2
$60billion must be raw materials.... ... Maybe you have to buy the cables seperately!
Batteries not included right?
Cargo model seems 'reasonable'
Perhaps some kind of hybrid using this to accellerate a rocket? Could save a lot of rocket fuel (and rocket) it you gave one a running start. Wonder if that could be incorporated into the cargo model...full power for cargo and partial plus rocket for people?
Why would anyone shit themselves on the ride up? According to TFA, when they hit the atmosphere, there'll be a 3g acceleration force felt. 3g isn't much to humans; that's like an amusement park ride.
If you're talking about the acceleration the train undergoes before exiting the launch tube and hitting the atmosphere 12 miles up, that's probably quite a bit less. 5 minutes to space is a pretty long time compared to the time a rocket does it in, and humans are able to withstand those forces with no trouble.
One thing I don't understand: Why build a linear track that is 1000 km long when you could build a much much shorter loop instead? The lateral G force will be a problem, but it has to be cheaper to solve than building a track across most of Europe. You can then spit the train out on a shorter (and elevated) linear section for the last bit.
Floating superconducting tracks 25km up in the air is total lunacy however.
I read the internet for the articles.
It looks like the "murder squad" missed a couple of details.
Tethers; The article says that UHMWPE will be fine for the tethers. There is one aspect of UHMWPE that makes it completely unsuitable for those tethers; it is called creep. As long as the tethers are under tension UHMWPE will permanently deform getting longer and longer. At some point they will get thin enough to break. This would mean they would have to be replaced on a regular basis. How often is a factor of tension and heat. It may be that the down time will be so great that there will be no up time and replacing a 20 kM cable is no easy task. This would also mean that every line would have to have a massive tensioner to continually take up the extra slack.
Linear Accelerator;
I just love this quote "Maglev passenger trains have carried passengers at nearly 600 kilometers per hour (373 mph) - spacecraft have to be some 50 times faster, but the physics and much of the engineering is the same." One can't just take some numbers, multiply by 50 and assume they will work. That is like saying that we can make a 100 story building so making a 5000 story building would be easy as the "physics and much of the engineering is the same".There is already a problem with going a bit faster that what we do now. There is so much energy in the coils that sparks are forming that are welding the shuttle to the rails. Try to go 50 time that and you have much bigger issues.
The "murder squad" needs to take a closer look.
Thing is, everyone is focussing on the launch as the costly part; as if all the expense of the entire spaceflight was tied up in the first eight minutes of the journey. What about the re-entry? What about the on-orbit operations (communications, station keeping, life support (if applicable))? There is no toll booth in space where you pay one fee to go up, and another to go down. Practically all of the costs for the entire mission are up front costs. Fuel is so cheap that it is a rounding error three digits to the right compared to other components of the costs.
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Don't know if it's usable for this application, but there's an unpowered version of maglev in existence called "Inductrack" which uses no power, coils of wire in the track and permanent magnets in the vehicle, though of course it relies on the forward motion of the vehicle to achieve levitation.
It seems to me the more worrying problem is the power requirements for making the launch tube levitate, and what would happen if there were a power failure. A space elevator seems to make a lot more sense here, as it doesn't require millions of amps of current to stay stable and safe.
They said 3 g forward on the way up, 3 g backward when you hit the atmosphere. So on the way up you're in the tightest turn you've ever felt on a roller coaster for 5 minutes straight, then you suddenly get to experience it in exactly the opposite direction.
It would be a pretty wild ride. Nothing a reasonably healthy person couldn't take, but it would scare the hell out of most of the population.
The space shuttle, for comparison, had a maximum acceleration of about 3 g. So it would be like a shuttle ride, except for that 6 g switch when you slam into the atmosphere.
The shuttle cost about half a billion dollars to launch. Satellites that can do most of those things can be built as class projects in high school.
Rentry and human rated space capsules are a little harder, but still cheap compared to the infrastructure, design and effort (yes, fuel is not the only part, but all those launch costs go away) of actually launching anything.
The space shuttle, for comparison, had a maximum acceleration of about 3 g
You sure about that? Because the Space Shuttle reached orbit much faster than 5 minutes, so it seems like the acceleration should be somewhat more than this train (of course, the train is also traveling laterally some distance, so that would probably account for it).
Anyway, exactly how many people are going to be taking the space train anyway? Anyone who can't handle a roller coaster ride for 5 minutes straight probably shouldn't be going to space. Anyone too scared should definitely not be going to space, where they're going to go out of their mind when they experience weightlessness.
Still, it seems to me the space elevator makes more sense than this thing, though it relies on some advanced materials technology. With the SE, you don't have to worry about a giant catastrophe if the power fails, whereas this thing will have its launch tube fall 12 miles back to the earth (maybe parachutes could help here), not to mention the enormous power consumption for making the tube levitate.
"This thing would be far easier to build on Moon where gravitation is much lower and there is no atmosphere."
You know, it would be even easier to build it in orbit. It could be much smaller too, because getting to orbit requires much less delta v when you're already in orbit!
why cant they use balloons to keep the tube up? 20km is still in the atmosphere, and the highest balloon has gone to 34km. just have huge balloons all along the tube, with cables to the ground keeping it in line.
"You sure about that? Because the Space Shuttle reached orbit much faster than 5 minutes, so it seems like the acceleration should be somewhat more than this train (of course, the train is also traveling laterally some distance, so that would probably account for it)."
Yes. And no, the space shuttle took longer than 5 minutes to reach orbit, and took a big shortcut by going straight up for the first bit. Haven't you ever watched a launch?
http://en.wikipedia.org/wiki/Orders_of_magnitude_(acceleration)
http://en.wikipedia.org/wiki/Space_Shuttle#Launch
No, the proposal for this thing is as big as it is specifically so that people can ride it. But it very well might make the average person "shit his pants" as the OP said. As for space elevators, they are currently impossible, whereas this thing is probably possible to build. Also, a ride up a space elevator might take a couple of weeks, while this thing gets you there in 5 minutes. As for energy, it's levitated with superconductors, so there is no ongoing energy cost except for the cryogenics, and if the power fails, well, nothing happens.
Instead of a levitated tube use more conventional means, balloons filled with hydrogen or helium. Let the balloons float it up, tethers hold it down and on target.
That should take a huge challenge out of the requirements. Balloons are cheap to build and maintain. They have a very low failure rate and the failure mode is very controllable with redundancy eg two balloons for each support node with heavy weights on them that can be dropped.
Really the entire structure could be held above ground in this way. Floated and tethered means no earthquake fears, no need to claim right of way, less environmental impact, no digging or foundation work, etc etc. just build the tube, build a tower as its start point then extend it straight out into space with more tube/track. Would be a perfectly straight line that does not follow curvature of the planet.
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Ok, I took a brief look at TFA but I'm not sure about the configuration.
It seems like they accelerate the "train" MOSTLY on the ground but then continue accelerating the craft up the final 12 miles. That requires the vacuum proof "tube" for the 12 mile vertical lift to be heavy and carrying a lot of power hungry superconducting magnets (and the final plasma curtain). No wonder they have to use such ginormous magnets to keep it aloft!
Why not do ALL of the acceleration on the ground and then, sort of gently redirect the train up the tube taking it to space. Then the last leg of the tube need not be anything than a (thin) wall keeping the air out with possibly some minor magnets just to keep the vehicle centered. Of course this will require the train to be set on a parabolic(?) path by the final set of propulsion magnets and will require some sort of tall, gently sloped "ramp" in order to do so in a manner that won't cause excessive g-forces but I imagine this ramp would be a lot shorter than 12 miles!
By the way, if you wanted to accelerate the train up to an appreciable fraction of orbital velocity in a CIRCULAR track, how big a ring would it have to be to keep the centripedal acceleration under 3g's. Didn't they ALREADY COMPLETE that 50 MILE in circumference tunnel for the SCC (super conducting collider) in Texas before congress axed the budget? I mean, the thing is already practically designed and built (instead of accelerating tiny particles to a very high fraction of c, use it to send much heavier things much slower)! If the g-forces are too high for humans, it could still be used for cargo.
Yeah, why should we build long lines of iron bars across the country when the problem of transportation has already been solved with horse carriages?
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5 minutes to space is a pretty long time compared to the time a rocket does it in
It isn't. For a Space Shuttle launch, MECO (main engine cut-off) was about 8 minutes after lift-off.
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Hmm, that's odd. I saw a video a while ago taken from a rocket (Titan, I think, launching a satellite), and it was amazing how fast it went from the ground up to space. Maybe they sped it up, or maybe those unmanned rockets rise faster?
The incident with Babble occurred due to the hubris of man (don't kill me for using a Greek term). Maybe they touch on it here, http://ocw.mit.edu/courses/literature/21l-458-the-bible-spring-2007/ although I do not know. And yeah, I know you were attempting a joke, but it is not a very good one: maybe with delivery it could be--plenty of bad jokes are funny because of the joker, but I figure someone might be interested in the MIT link. Don't know how well an engineering institution will pull-off teaching on literature and biblical stuff (mesuspects that some traditionalist--though not fundamentalists, religious organizations would probably do a whole lot better, but again, don't know). Now that I have said all I don't know, I'll have to put that MIT course on my own to-do/listen/watch/whatever list, but it could take a while to get to (stupid priorities).
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Yep, unmanned rockets can and often do accelerate quite a bit faster.
However, humans are not able to withstand those foces without trouble,
so if you want to ride along, 5-8 minutes will have to do.